docs: def get_versions():
          """Return the list of supported PDF versions.
          See :meth:`restrict_to_version`.
  
          :return: A list of :ref:`PDF_VERSION` strings.
  
          *New in cairo 1.10.*
  
          """
          versions = ffi.new('cairo_pdf_version_t const **')
          num_versions = ffi.new('int *')
          cairo.cairo_pdf_get_versions(versions, num_versions)
          versions = versions[0]
          return [versions[i] for i in range(num_versions[0])]